| Nanomaterials, as the foundation for the development of nanoscience, have been rapidly expanding themselves with the rapid development of nanoscience and nanotechnology for the past decade. Quantum Dots (QDs), a new kind of fluorescent nanomaterials, have great applications in bioanalytical chemistry and become a hot and exciting research field in nanomaterials and nanobiomedicine because of their extraordinary fluorescent properties.Compared with conventional organic fuorophores, QDs offer several unique advantages, such as a wide excitation spectrum, and a narrow, tunable, symmetric emission spectrum, size-and composition-tunable emission from visible to infrared wavelengths, large absorption coefficients across a wide spectral range, multicolor emissions under single excitation light, large stokes shifts, long fluorescence lifetime, and very high levels of brightness and photostability, and so on. Hydrophilic solubilization of QDs in organic phase plays the key rule in their application in biochemistry with mature development of synthesis procedures of high quality hydrophobic QDs.This thesis report works as follows:①Adopting amphiphilic surfactants as raw modifying reagents, on the basis of hydrophobic interaction between surfactants and non-polar organic ligands existing on the surface of QDs, high quality hydrophilic solubilization of CdSe/ZnS QDs was achieved by very simple method.②The water-soluble QDs have high fluorescence quantum yield, the fluorescence intensity has good salt stability and little effect by the pH.③We successfully constructed a pair of quantum dot bio-probes by using EDC as coupling agent, QDs-Tf can be used to label tumor cells and QDs-CaM can be used to construction new FRET donor-acceptor pair.④QDs-protein’s binding ratio was determined by the dying method with coomassie brilliant blue.The study of interaction between metal ions and biological macromolecules is a new frontier of chemistry and life science. Transferrin(Tf) is a combination of non-heme iron glycoprotein. The main function of Tf is combing free ferric irons. In the normal physiological state, human serum Tf is only 30% saturated by ferric irons, so that it can combine the other metal ions in human blood.With the growing application of rare earth, a growing number of them enter into the environment, into the food chain. Rare earth first contact the blood, which were ingested through the food chain. With the function of transportation and immunity, Tf may become the ligand to rare earth ions. Research on the combination of rare earth ions with Tf for rare earth ions on the biological effects is of great significance.The existed researches on the interaction between rare earth ions and Tf mainly used the UV difference spectroscopy. UV difference spectroscopy was extensive used to probe the interaction between ions and Tf. If some metal ions also bind the non-ferric ion binding sites in Tf, UV difference spectroscopy could not provide any signal change.In our experiments, Cu2+-ion selective electrode was used to detect the unbound Cu2+in Cu2+-Tf system. The average number of metal ions bound per transferrin molecule and equilibrium constant were obtained by saturation curve combined with MATLAB non-linear least squares. Our results should be more reliable than that of UV difference spectroscopy. The main results are as follows:①Tf molecule could bind not only two Cu2+ions in ferric ion-binding sites, but also about seven non-specific binding sites.②The results showed that the synergistic ions (bicarbonate) can promote the combination between Tf and ions. In the absence of synergistic ions, the calcfated equilibrium constants are:1gK1=8.78, 1gK2=7.86, 1K3=7.34,1gk6=6.98, 1gK5=6.67, 1gK6=6.32, While, in the presence of synergistic ions, the calculated equilibrium constants are:1gK1=9.42, 1gK2=8.75, 1gK3=8.26, 1gK4=7.89, lgK5=7.54, 1gK6=7.2, 1gK7=6.84, 1gK8= 6.46, 1gK9=6.11, 1gK10=5.70.③The ion competition with the rare earth metal showed that all rare earth ions could bind to A sites of Tf. The binding constants of rare earth ions to Tf calculated by MATLAB program are little diversity. It is of great significance for the study of the biological effects of rare earth ions. |
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